UPDATE: It has now been confirmed that Waters Of Mars will be screening on Sunday, the 15th of November. (We were only one day out! Original story follows)

It's been quite a wait since the tepid Planet Of The Dead for the second of this year's promised Doctor Who specials. And with an intriguing trailer, plus the fact that it's effectively the beginning of David Tennant's farewell trilogy, The Waters Of Mars looks like it could be something really quite interesting.

But when, we've been wondering for some time, will the BBC show it? Originally it was pegged for October, but then Russell T Davies mentioned earlier this year that it was down for November. Then we might be getting a taster for it on Children In Need. That all hinted towards the end of November for the episode's transmission.

However, the clues are now pointing towards 14th November 2009. We say this having not had official confirmation from the BBC or anything like that, but just by doing a piece of detective work ourselves.

Firstly, the BBC lists the show, we understand, as for week 46. That, if we read BBC dates right, makes it the week commencing 14th November 2009, and would mean the latest it would be shown is 20th November. Given that, aside from Christmas, Doctor Who lives on Saturday nights, that's a very big pointy arrow in the direction of the 14th, then.

A further hint has come with the news that Children In Need this year, broadcasting on Friday 20^th November, will be previewing the Christmas specials instead. It's not going out on much of a limb to suspect that a reason for this will be that The Waters Of Mars will already have screened.

If The Waters Of Mars - complete with knocking four times, of course - is set for 14th November, as we now strongly suspect, then the BBC is likely to confirm it by the end of the week, when it releases details about its programming for that week.

How exciting... (unless, of course, we end up with egg on our face over the date...!)